Color detection apparatus

ABSTRACT

A chip sorting apparatus is disclosed. The apparatus includes an article transport mechanism, a light source positioned to direct light across surfaces of transported articles, and a detector positioned to detect light reflected from such surfaces and emit signals each indicative of a spectrum of light reflected by one such article as such articles are transported. A signal analyzer compares detector signals with stored data representative of the colors of articles of a set of articles being sorted. The analyzer emits article identifying signals reflective of such comparison. The apparatus also includes a sorter which is responsive to such identifying signals and directs identified articles from the transport mechanism into appropriate ones of a set of collection stations. A method of sorting a set of articles according to color is also disclosed.

This invention concerns colour detection apparatus, particularly but notexclusively apparatus for sorting different coloured articles, andespecially apparatus for sorting different coloured gambling chips.

Prior arrangements for automatically sorting coloured gambling chipshave generally used a plurality of photocells, usually three cells eachhaving a respective filter to detect respectively red, yellow and greenlight. This arrangement is relatively unsophisticated and problems canoccur in detecting different coloured chips and especially relativelysimilar colours. Particular difficulties can also be encountered whensome chips of a particular colour have become faded and/or dirtyrelative to other chips due perhaps to the chips being of differentages. Colour variations can also occur between different batches of aparticular colour chip. Further difficulties have also been experiencedwith chips with different coloured faces on each side, or chips bearingordered or random patterns.

When the `colour of an article` is referred to in this specification,this may include an article of more than one colour and/or one whichbears a pattern.

According to the present invention there is provided colour detectionapparatus, the apparatus comprising means for detecting light intensitysubstantially across the visible spectrum and means for comparing theread light intensity relative to a previously read light intensitysubstantially across the visible spectrum.

Means are preferably provided for comparing the read light intensitywith previously read light intensities for one or more known colours.

Means are preferably provided for reading the light intensity at aplurality of closely spaced intervals across the visible spectrum. Thelight intensity can preferably be read at over twenty spaced intervals,desirably over fifty spaced intervals, and more particularlysubstantially sixty four spaced intervals.

Preferably means are provided for splitting the light into one or morespectra.

Diffraction means may be provided for splitting the light into one ormore spectra, and desirably a diffraction grid is provided. Means arepreferably provided for focusing light onto the diffraction grid.

Where the light is split into more than one spectra, the apparatus ispreferably arranged to read the light intensity across respective partsof adjacent spectra, desirably with the red end of a one spectra beingread along with the blue end of a larger spectra. The apparatus maycomprise a visible detector capable of measuring light intensity at aplurality of closely spaced intervals, for measuring the respectivelight intensities across the spectrum or the respective parts of eachspectra.

The invention also provides apparatus for detecting the colour of anarticle, the apparatus comprising colour detection apparatus accordingto any of the preceding six paragraphs.

The apparatus preferably comprises means for shining light onto thearticle.

The apparatus is preferably arranged such that the colour is read for atleast part of the article. Means are preferably provided for moving thearticle relative to the detection apparatus during colour detection,such that colour is read across at least part of the article.

The detection apparatus may be arranged to record the colour detected,i.e. the intensity and frequency, and the positioning of the article, soas to detect changes in colour and/or pattern across the article. Theapparatus preferably comprises means for differentiating the colourdetected relative to the position on the article so as to indicatecolour changes.

The apparatus preferably also comprises means for comparing the colourdetected with a plurality of previous colour detections of articles,with the articles at different orientations.

The apparatus may also be arranged to include the detected colour of anarticle in subsequent comparisons, whereby to update the apparatus iffor example the colour of article is changing due to dirt, fading ordifferent light conditions.

The invention further provides apparatus for sorting different colourarticles, the sorting apparatus comprising apparatus for detecting thecolour of an article according to any of the preceding four paragraphs,and means for automatically directing the article to a required locationin response to the colour detected by said colour detecting apparatus.

The apparatus may comprise means for allocating values to articles, andinputting into the apparatus which colour or colours of article haveeach value; and means for directing articles of each value to arespective required location.

The apparatus preferably also comprises means for recording how manyarticles of each value and/or colour have been sorted by the apparatusover a given time period.

The sorting apparatus preferably comprises means for automaticallysupplying articles to the colour detecting apparatus. A receptacle maybe provided for the articles, and from which the supply means takes thearticles. A movable continuous member may be provided extending throughthe receptacle for supplying the articles to the colour detectingapparatus.

A plurality of article holders may be provided on the continuous member.Means may be provided for providing a required tension in the continuousmember, and said member may comprise a chain.

The sorting apparatus preferably comprises means for automaticallydirecting an article to a respective one of a plurality of locations inresponse to the colour detected.

The sorting apparatus may comprise a plurality of engagement membersrespectively operable in response to the colour detected to move anarticle off a one of the holders such that the article is directed to arespective required location. The engagement members may be locatedsubstantially in line downstream of the colour detecting apparatusrelative to the continuous member, desirably with a plurality ofrespective receiving areas on the opposite side of the continuous memberthereto. The engagement members may be selectively engageable withsprung pusher members on the article holders for removing an articletherefrom.

The sorting apparatus is preferably arranged such that articles aredirected to a respective location if their colour corresponds to thecolour of an article whose colour has been previously detected andrecorded during programming of the apparatus. The apparatus may bearranged such that a range of shades and/or intensities of a particularcolour article can be detected and recorded during programming, to settolerances for an article being detected as corresponding to aparticular colour. Alternatively, or in addition, means may be providedto permit the tolerance of the range of colours considered ascorresponding, to be varied.

The sorting apparatus is preferably arranged such that all articleswhich have not previously been directed to a respective requiredlocation subsequent to passing the colour detection apparatus, areautomatically directed to a final location or returned to thereceptacle. An end engagement member is preferably engageable with eacharticle holder downstream of the required locations for receivingarticles.

A limited clearance may be provided either side of the continuous memberupstream of the colour detecting apparatus to ensure that articles arecorrectly aligned in the article holders prior to passing saidapparatus, and that only one article is located in each holder.

Means are preferably provided in the apparatus for electrostaticallycollecting dust and dirt.

The dust collecting means is preferably electrostatically charged byvirtue of movement of the continuous member.

The dust collecting means preferably comprises a collecting member of areadily electrostatically chargeable material, for example nylon.

The collecting member may comprise the end engagement member, which maycomprise a cam engageable with the pusher members on the articleholders, said engagement causing the electrostatic charging of the endengagement member.

Means may be provided for automatically stopping movement of thecontinuous member if resistance to movement thereof above apredetermined limit is detected. The sorting apparatus may be arrangedsuch that movement of the continuous member is reversed for a shortperiod following detection of such increased resistance with a view toclearing any blockage of articles.

The sorting apparatus is preferably computer controlled and means may beprovided for converting analog signals received from the colourdetection apparatus to digital signals for comparison.

Still further according to the present invention there is providedapparatus for sorting different colour gambling chips, the apparatusbeing according to any of the preceding twenty two paragraphs.

The chip sorting apparatus preferably comprises a rack or other chipholder into which the chips are delivered, with each colour chip beingdelivered to a respective part thereof.

The invention further provides a method for checking the colour of anarticle, the method comprising detecting the colour intensity of thearticle substantially across the visible spectrum, and comparing theread colour intensity with a previously read colour intensitysubstantially across the visible spectrum of an article of a knowncolour to ascertain whether the checked article is of the same colour.

The read colour intensity is preferably compared relative to previouslyread colour intensities of an article at a plurality of differentorientations and/or a plurality of articles.

The light intensity is preferably read at a plurality of closely spacedintervals across the visible spectrum. The light intensity is preferablyread at over twenty spaced intervals, desirably over fifty spacedintervals, and more particularly substantially sixty four spacedintervals.

Light is preferably shone on the articles to be detected, and the lightreflected from the articles is preferably split into one or morespectra.

Where the light is split into more than one spectra, the light intensityis preferably read across respective parts of adjacent spectra,desirably with the red end of a one spectra being read along with theblue end of a larger spectra.

The colour intensity is preferably read across at least part of thesurface of the articles. The colour intensity may be detected relativeto the location on the articles. The colour intensity read is preferablydifferentiated relative to the location on the article so as to indicatecolour changes. Only colour changes may be stored from previouslychecked articles, such that only colour changes are compared.

The previously read colour intensities are preferably automaticallyupdated if variations are noted in subsequent colour intensities forarticles of the same colour.

Tolerances may be set for deciding whether an article is of the samecolour as a previously detected article, and the tolerances may beadjustable.

The method is preferably computer controlled.

An embodiment of the present invention will now be described by way ofexample only with reference to the accompanying drawings, in which

FIG. 1 is a diagrammatic cross-sectional view of colour detectingapparatus according to the invention;

FIG. 2 is a plan view of the apparatus of FIG. 1;

FIG. 3 is a diagrammatic partially cut-away side view of apparatus forsorting gambling chips according to the invention and incorporating theapparatus of FIG. 1;

FIG. 4 is a diagrammatic front view of part of the apparatus of FIG. 3;and

FIG. 5 is a diagrammatic rear view of part of the apparatus of FIG. 3.

FIGS. 1 and 2 show colour detecting apparatus 10 suitable for detectingfor example the colour of a gambling chip located approximately at X.The apparatus 10 comprises a mounting bracket 12 above which is locatedan electric lamp 14. A passage 16 is located in front of the top part ofthe lamp 14 to receive light therefrom.

A collimator 18 is provided at the far end of the passage 16. Beyond thecollimator 18 is a downwardly angled mirror 20 which directs light fromthe lamp 14 downwardly to X. The mirror 20 is located in a housing 22which extends beyond X. The housing 22 mounts a further passage 24beyond and facing X, with a narrow opening 26 on the end thereof facingX. A diffraction grid 28 is provided towards the other end of thepassage 24 between two convex lenses 30. A broader passage 32 extends ata downward inclination from the end of the passage 24 with a sixty fourposition visible detector 34 at the far end thereof.

FIGS. 3-5 show a gambling chip sorting apparatus 36. The apparatuscomprises a plate 38 inclined downwardly and outwardly at a relativelysteep gradient. A continuous member in the form of a chain 40 extends ina loop over the plate 38 substantially adjacent the edge thereof. Thechain 40 is movable in an anti-clockwise direction from a horizontalupper pass 42, to a long vertical down pass 44, to a gradual upwardlyinclined portion 46 to a short vertically upwards extending portion 48.The chain 40 is drivable by a motor 50 through a gearbox 52. Anautomatic chain tensioning device 54 is provided in engagement with thechain 40. A plurality of holders (not shown) are provided on the chain40 with a suitable size circular recess in each for carrying a gamblingchip. A sprung pusher member is provided in each holder and arranged soas to eject a chip from the holder when pushed against the spring force.

An open topped bin 56 with substantially vertical sides is provided onthe front side of the plate 38 with the chain 40 running through theinterior thereof. A paddle (not shown) may be provided in the binadjacent the connection between the pass 44 and portion 46 to directchips into the holders.

A plate 58 is provided spaced from the plate 38 a short distance fromthe chain 40 such that there is limited clearance between the plate 58and holders passing thereby. The plate 58 thereby ensures that any chipscarried by the holders are in correct alignment, and only one chip canbe carried by each holder. The plate 58 is located at the far right handend as shown in FIG. 4 of the upper pass 42. Immediately downstream ofthe plate 58 is the measuring apparatus 10. Downstream of the apparatus10 are ten chip directing stations (not shown in detail). Each of thestations comprises a solenoid 60 operated finger (not shown) engageablewith the sprung pusher members on the holders to push a chip off theholder. The fingers are generally located behind and slightly above theplate 38 such that chips are pushed in a direction out of the page asshown in FIG. 4.

Opposite each of the fingers and extending in a direction out of thepage as shown in FIG. 4, are a plurality of racks (not shown) to acceptthe different chips. The apparatus 36 is arranged such that if a chiphas not been urged from a holder at a one of the directing stations,either the chip is urged off the holder at the most downstream directingstation, or the chip is urged back into the bin 66 before leaving theupper pass 42.

To provide this final ejection a nylon cam member 67 (FIGS. 3 and 5) isprovided downstream of the chip directing stations. The cam member 67 isengageable with each sprung pusher member on the article holders toeject any remaining chips therefrom.

The cam member 67 provides a dual roll in that it also collects dust anddirt in the apparatus 36 by electrostatic attraction. The regularenagement of the pusher members, during operation of the apparatus 36,against the member 67 causes an electrostatic charge thereon. Dirt/dustcan readily be removed from the member 67 when the apparatus 36 isswitched off.

The apparatus 36 is mounted on a base 62 with wheels 64 to enable readymovement thereof for example to adjacent a roulette table or elsewhere.

In use, the apparatus 36 is programmed as follows. Each directingstation is programmed to a relevant colour chip by detecting andrecording the colour of a sample chip placed in the apparatus 10. Aplurality of sample chips of each colour may be detected to provide arange of recordings to set tolerances to accept variations of intensityor tone etc. for a particular colour. If required it may be possible tomanually adjust the tolerance for any or all colours. Once eachdirecting station has been programmed to be actuable for a respectivecolour, the apparatus 36 is ready for operation.

Used chips are directed into the bin 56. The chips are taken up by theholders carried by the chain 40, perhaps with the assistance of thepaddle. The chips are then carried by the chain 40 past the plate 38 toensure correct alignment.

The colour of the chips is then detected by the apparatus 10 in thefollowing manner. Light from the lamp 14 is focused in the collimator 18and reflected onto the chip by the mirror 20. Colour is detected aschips move past the apparatus 10 such that colour is detected over arectangular area on the chips. Light reflected from the chip 20 passesthrough the opening 26 and subsequently through the lenses 30 anddiffraction grid 28 sandwiched therebetween. Light passing through thegrid 28 is diffracted to produce a plurality of spectra to be read bythe detector 34.

The detector 34 is arranged to measure light intensity of the red end ofa first spectra and the blue end of an adjacent further larger spectra.The detector 34 is arranged to measure across the whole visible spectrumthough in two different spectra. Measuring the larger spectra for theblue end permits a greater number of readings in this area whereaccurate measurements are more typically difficult to obtain. Thedetector 34 measures the light intensity at sixty four positions acrossthe respective spectra, and produces an analog signal which is sent to acontrol computer (not shown).

The control computer converts the analog signal to a digital signal andcompares this with the signals previously recorded for the colours ofthe chips measured during programming. If the colour of a chip beingmeasured corresponds within the tolerances of a one of the previouslyprogrammed coloured chips, a signal is sent to the appropriate directingstation such that when the corresponding holder is adjacent therespective station, the finger is actuated to move the chip off theholder and into the appropriate place in the storage rack.

The directing stations may be allocated values, and one or morepreviously read colours may be programmed as having a respective value.This enables different colour/shades of chips to be used for the samevalue, and is useful with chips which may be differently coloured oneach side.

The apparatus may be programmed to provide statistical information suchas how many chips of each colour and/or value have been sorted over agiven period.

The apparatus may also be programmed to automatically update previouslyread colours when the apparatus detects that the colours ofcorresponding chips gradually changes due for example to the chipsbecoming dirty and/or fading.

The computer operates in real time to perform this function and meansare provided to either accurately control the speed of movement of thechain 40 and/or to detect very accurately this speed. As noted above ifthe colour of the chip detected does not correspond to any of thecolours previously detected during programming, the chip is eitherejected into a final column of the rack or is returned into the bin 56.

There is thus described apparatus for sorting gambling chips with anumber of advantageous features. The apparatus is wholly programmableand can be programmed by detecting the colour of a variety of chips ofthe same colour to be able to accurately detect chips of the same coloureven with variations due perhaps to dirt, age or any manufacturingvariations. Measurement across the whole visible spectrum provides formuch more accurate detection and means relatively similar colours can bereadily distinguished.

As noted above colour is detected over an area on the chips as the chipsmove past the detecting apparatus 10. The colour may be detectedrelative to the position on the chip, during movement thereof,preferably with the colour being detected at a large number of discretepoints. The colour read, i.e. intensity and frequency, may bedifferentiated relative to the position on the chip, i.e. the distancetravelled thereby, so as to indicate changes in colour, and the amountthereof. The changes in colour will generally denote boundaries betweencolours on the chips.

This system is therefore useful with patterned chips, whether random orordered. In practice only the colour changes will be stored and hencecompared. With random patterns, the colour of which previously hasgenerally not been detectable, it would be necessary to initially recordall chips for example at a particular casino, at a large number ofdifferent orientations.

Apparatus according to the invention could be used to sort a wide.variety of articles other than gambling chips. Furthermore, colourdetection apparatus according to the invention could be used in a widerange of other applications. Apparatus according to the invention couldbe used for example in quality control and perhaps in production tolocate extraneous articles. The apparatus could be used to detectcolours other than of articles, such as for example of gases or otherarrangements. The system measuring colour relative to position is veryuseful in verifying patterned items such as bank notes.

The detection across the spectra provides for a very accurate andsensitive detection. Furthermore, the detection across the blue end ofthe spectra in a larger spectra relative to the red end provides forgreater sensitivity in this part of the spectrum which is generally moredifficult to measure. The programmability of the apparatus obviouslymakes it particularly flexible.

Whilst endeavouring in the foregoing specification to draw attention tothose features of the invention believed to be of particular importanceit should be understood that the Applicant claims protection in respectof any patentable feature or combination features hereinbefore referredto and/or shown in the drawings whether or not particular emphasis hasbeen placed thereon.

What is claimed is:
 1. Colour detection apparatus for detecting thecolour of gambling chips and sorting such chips, comprising:a) means fordetecting light intensity substantially across the visible spectrum; b)means for comparing a read light intensity relative to a previously readlight intensity substantially across the visible spectrum; c) means forsplitting the light into one or more spectra; d) means for automaticallydirecting such chips to a required location in response to colourdetected; and, e) a chip holder into which such chips are delivered,with each colour chip being delivered to a respective part of theholder.
 2. Colour detection apparatus for detecting the colour ofarticles and sorting such articles comprising:a) means for detectinglight intensity substantially across the visible spectrum; b) means forcomparing a read light intensity relative to a previously read lightintensity substantially across the visible spectrum; c) means forsplitting the light into one or more spectra; d) means for automaticallydirecting such an article to a required location in response to colourdetected; e) means for automatically supplying articles to the colourdetecting apparatus; f) a receptacle for such articles from which thesupply means takes the articles; g) a movable continuous memberextending through the receptacle for supplying the articles to thecolour detecting apparatus; and, h) a plurality of article holders onthe continuous member.
 3. Apparatus according to claim 2, characterisedin that the sorting apparatus comprises a plurality of engagementmembers respectively operable in response to the colour detected to movean article off a one of the holders such that the article is directed toa respective required location.
 4. Apparatus according to claim 3,characterised in that the engagement members are located substantiallydownstream of the colour detecting apparatus relative to the continuousmember.
 5. Apparatus according to claim 4, characterised in that theengagement members are located with a plurality of respective receivingareas on the opposite side of the continuous member thereto. 6.Apparatus according to claim 3, characterised in that the engagementmembers are selectively engageable with sprung pusher members on thearticle holders for removing an article therefrom.
 7. Apparatusaccording to claim 3, characterised in that an end engagement member isengageable with each article holder downstream of the stations. 8.Apparatus according to claim 7, characterised in that the end engagementmember is a collecting member.
 9. Apparatus according to claim 8,characterised in that the end engagement member comprises a camengageable with pusher members on the article holders, said engagementcausing the electrostatic charging of the end engagement member.